Liquid droplet jetting apparatus and liquid droplet jetting state inspection unit

Abstract

A liquid droplet jetting apparatus includes: a liquid droplet jetting head which has a liquid droplet jetting surface on which a plurality of nozzles are open and aligned in a row in a first direction; and a liquid droplet jetting state inspection unit which inspects liquid droplet jetting state of each of the nozzles, including: a liquid droplet landing body which has a landing surface facing the liquid droplet jetting surface and on which the liquid droplets jetted from each of the nozzles land, and which is configured to be relatively movable, with respect to the liquid droplet jetting head, in a second direction which is parallel to the liquid droplet jetting surface and intersects the first direction; and a landing detection mechanism which detects whether or not the liquid droplets have landed on a predetermined detection area provided on the landing surface of the liquid droplet landing body.

What is claimed is: 
     
       1. A liquid droplet jetting apparatus which jets liquid droplets, comprising:
 a liquid droplet jetting head which has a liquid droplet jetting surface on which a plurality of nozzles are open and aligned in a row in a first direction; and 
 a liquid droplet jetting state inspection unit which inspects liquid droplet jetting state of each of the nozzles, including: 
 a liquid droplet landing body which has a landing surface facing the liquid droplet jetting surface and on which the liquid droplets jetted from each of the nozzles land, and which is configured to be movable, with respect to the liquid droplet jetting head, in a second direction which is parallel to the liquid droplet jetting surface and intersects the first direction; and 
 a landing detection mechanism which detects whether or not the liquid droplets have landed on a predetermined detection area provided on the landing surface of the liquid droplet landing body; 
 wherein the detection area of the landing surface has a first edge which extends in a direction inclined toward the second direction with respect to a third direction which is orthogonal to the second direction. 
 
     
     
       2. The liquid droplet jetting apparatus according to  claim 1 , further comprising:
 a position detection mechanism which detects a position of the liquid droplet jetting head in the second direction with respect to the liquid droplet landing body; and 
 a judging section which judges the liquid droplet jetting state of each of the nozzles, based on a detection result of the landing detection mechanism; 
 wherein the judging section judges whether or not a liquid droplet jetting direction of each of the nozzles is inclined with respect to a predetermined direction, based on a position of the liquid droplet jetting head in the second direction with respect to the liquid droplet landing body at the time when one of the liquid droplets has been detected to have landed on the first edge by the landing detection mechanism. 
 
     
     
       3. The liquid droplet jetting apparatus according to  claim 2 ;
 wherein, in a state that the liquid droplet jetting head and the liquid droplet landing body have been moved relatively in the second direction while jetting the liquid droplets continuously from one of the nozzles, the landing detection mechanism detects that one of the liquid droplets has landed on the first edge by detecting a timing at which the liquid droplets start to land on the detection area or a timing at which the liquid droplets start to land on outside the detection area. 
 
     
     
       4. The liquid droplet jetting apparatus according to  claim 1 ;
 wherein the detection area is provided as a plurality of detection areas, on the landing surface of the liquid droplet landing body, aligned in the third direction leaving spaces therebetween; and 
 wherein the landing detection mechanism detects landings of the liquid droplets on the detection areas separately. 
 
     
     
       5. The liquid droplet jetting apparatus according to  claim 4 ;
 wherein the plurality of detection areas correspond to the plurality of nozzles respectively. 
 
     
     
       6. The liquid droplet jetting apparatus according to  claim 1 ;
 wherein the detection area of the landing surface has a second edge extending in a direction which intersects with the second direction and which is different from the direction in which the first edge extends. 
 
     
     
       7. The liquid droplet jetting apparatus according to  claim 6 ;
 wherein the second edge extends in the third direction. 
 
     
     
       8. The liquid droplet jetting apparatus according to  claim 2 ;
 wherein the liquid droplet jetting head is configured to be movable in the second direction and the position detection mechanism detects the position of the liquid droplet jetting head in the second direction. 
 
     
     
       9. The liquid droplet jetting apparatus according to  claim 1 ;
 wherein an angle made by the first edge with respect to the third direction is 45° or more, but less than 90°. 
 
     
     
       10. The liquid droplet jetting apparatus according to  claim 1 ;
 wherein the liquid droplet jetting surface of the liquid droplet jetting head faces the landing surface of the liquid droplet landing body in a vertical direction; and 
 wherein the landing surface is inclined with respect to a horizontal surface. 
 
     
     
       11. The liquid droplet jetting apparatus according to  claim 1 ;
 wherein at least the detection area of the landing surface is covered by a liquid repellent film. 
 
     
     
       12. The liquid droplet jetting apparatus according to  claim 1 ;
 wherein the liquid droplet landing body has a vibration plate, one surface of which is the landing surface facing the liquid droplet jetting surface; 
 wherein the landing detection mechanism detects deformation of the vibration plate under a condition that the liquid droplets have landed on the landing surface; and 
 wherein one edge of the vibration plate extends, in the direction inclined toward the second direction with respect to the third direction, to form the first edge of the detection area. 
 
     
     
       13. The liquid droplet jetting apparatus according to  claim 12 ;
 wherein the liquid droplet jetting state inspection unit has a supporting member which extends in the third direction; and 
 wherein the vibration plate is cantilever-supported at one-end portion thereof by the supporting member. 
 
     
     
       14. The liquid droplet jetting apparatus according to  claim 12 ;
 wherein the landing detection mechanism has a piezoelectric element provided to the vibration plate. 
 
     
     
       15. The liquid droplet jetting apparatus according to  claim 14 , further comprising:
 a drive unit which drives the piezoelectric element; 
 wherein, after the liquid droplets jetted from each of the nozzles have landed on the landing surface of the vibration plate, the drive unit drives the piezoelectric element to vibrate the vibration plate. 
 
     
     
       16. The liquid droplet jetting apparatus according to  claim 1 ;
 wherein the landing detection mechanism has: 
 a light emitting element which irradiates light toward the liquid droplet landing body; and 
 a light receiving element which receives light irradiated from the light emitting element; and 
 wherein the landing detection mechanism detects a change in an amount of light received by the light receiving element under a condition that the liquid droplets have landed on the detection area. 
 
     
     
       17. The liquid droplet jetting apparatus according to  claim 16 ;
 wherein the liquid droplet landing body, at least in the detection area, is made of a material which allows light to pass through in a thickness direction thereof; 
 wherein the liquid droplets jetted from the nozzles have a light shielding property; and 
 wherein the light emitting element and the light receiving element are arranged to sandwich a portion, of the liquid droplet landing body, in which the detection area is provided, in a direction orthogonal to the landing surface. 
 
     
     
       18. The liquid droplet jetting apparatus according to  claim 2 , further comprising:
 a recovery mechanism which recovers jetting performance of the nozzles by discharging liquid from the nozzles; 
 wherein, under a condition that the judging section judges that a liquid droplet jetting direction of a certain nozzle is inclined, the recovery mechanism performs a recovery operation for the certain nozzle. 
 
     
     
       19. The liquid droplet jetting apparatus according to  claim 18 ;
 wherein the recovery mechanism is configured to be performable two types of recovery operations with different liquid discharge performance; and 
 wherein the recovery mechanism performs selectively one of the two types of recovery operations based on a judgment result of the judging section. 
 
     
     
       20. The liquid droplet jetting apparatus according to  claim 19 ;
 wherein the recovery mechanism firstly performs a first recovery operation for the certain nozzle with a first liquid discharge performance; and 
 wherein, under a condition that the judging section judges that the liquid droplet jetting direction of the certain nozzle is inclined after the first recovery operation has been performed, the recovery mechanism performs a second recovery operation for the certain nozzle with a second liquid discharge performance higher than the first liquid discharge performance. 
 
     
     
       21. The liquid droplet jetting apparatus according to  claim 19 ;
 wherein the detection area of the landing surface has a second edge extending in the third direction; 
 wherein the judging section judges whether the liquid droplet jetting direction of the certain nozzle is inclined at least in the third direction with respect to the predetermined direction or only in the second direction, based on positions of the liquid droplet jetting head in the second direction under a condition that one of the liquid droplets lands on the first edge and under a condition that another of the liquid droplets lands on the second edge; 
 wherein the recovery mechanism performs the first recovery operation with a first liquid discharge performance, under a condition that the judging section judges that the liquid droplet jetting direction of the certain nozzle is inclined only in the second direction; and 
 wherein the recovery mechanism performs the second recovery operation with a second liquid discharge performance which is higher than the first liquid discharge performance, under a condition that the judging section judges that the liquid droplet jetting direction of the certain nozzle is inclined at least in the third direction. 
 
     
     
       22. The liquid droplet jetting apparatus according to  claim 20 ;
 wherein the first recovery operation is a flushing operation for the nozzles; and 
 wherein the second recovery operation is a purge operation in which the liquid is discharged forcibly from the nozzles by applying a pressure to the liquid in the nozzles from outside of the liquid droplet jetting head. 
 
     
     
       23. A liquid droplet jetting state inspection unit which inspects liquid droplet jetting state of each of a plurality of nozzles of a liquid droplet jetting head having a liquid droplet jetting surface on which the nozzles are open and aligned in a row in a first direction, the unit comprising:
 a liquid droplet landing body which has a landing surface facing the liquid droplet jetting surface and on which liquid droplets jetted from each of the nozzles land, and which is configured to be movable, with respect to the liquid droplet jetting head, in a second direction which is parallel to the liquid droplet jetting surface and intersects the first direction; and 
 a landing detection mechanism which detects whether or not the liquid droplets have landed on a predetermined detection area provided on the landing surface of the liquid droplet landing body; 
 wherein the detection area of the landing surface has a first edge which extends in a direction inclined toward the second direction with respect to a third direction which is orthogonal to the second direction.